RFK Jr.'s vaccine panel votes no on thimerosal. What is that and why is there controversy?
A key vaccine committee, newly appointed by Health and Human Services Secretary Robert F. Kennedy Jr., voted against recommending certain vaccines that contain a preservative long targeted by anti-vaccine advocates despite broad scientific consensus on its safety.
The call against the preservative, called thimerasol, was first presented by Lyn Redwood, former leader of Children's Health Defense, an anti-vaccine group founded by Kennedy, during a June 26 meeting for the Advisory Committee on Immunization Practices.
She argued that thimerasol is a neurotoxin and the panel should recommend only thimerosal-free flu vaccines for all pregnant women, infants and children. The panel also voted the same recommendation for adults.
Health experts were shocked to see that thimerosal, a preservative that has largely been phased out of U.S. vaccines, was on the ACIP agenda when it was posted on the Centers for Disease Control and Prevention website June 25.
Before the vote, panel members argued back and forth on whether thimerosal is safe, despite scientific literature showing no link between vaccines containing the preservative and autism or other neurodevelopmental disorders.
Dr. Cody Meissner, the only ACIP member to reject the recommendation, said thimerosal has been used since World War II and “no study has ever indicated any harm.” He said removing thimerosal from all vaccines could reduce access and increase costs, especially in other countries where vaccine alternatives may not be available.
“You also have to consider what are the consequences of these sorts of recommendations,” Meissner said.
The eight new ACIP members met for the first time June 25. Kennedy fired all 17 original members of the committee on June 9 and appointed its new members, which included some vaccine skeptics, a few days later.
What is thimerosal? Is it safe?
Preservatives, such as thimerosal, are compounds that kill or prevent the growth of microorganisms, such as bacteria and fungi, according to the FDA. However, improvements in manufacturing technology have decreased the need to add such preservatives.
A CDC briefing document compiled by staff and posted on its website noted that in the 2024-2025 season, 96% of all influenza vaccines in the U.S. were thimerosal-free.
The agency says it has actively addressed the issue of thimerosal as a preservative and its use has significantly declined over the decades. All vaccines routinely recommended for children 6 and under are available in versions that don’t contain thimerosal, the FDA said.
While most vaccines don’t contain thimerosal, the agency states that “a robust body of peer-reviewed, scientific studies conducted in the United States and countries around the world support the safety of thimerosal-containing vaccines.”
“The scientific evidence collected over the past 20+ years does not show any evidence of harm, including serious neurodevelopmental disorders, from use of thimerosal in vaccines,” the FDA says on its website.
Dr. Sean O’Leary, chair of the American Academy of Pediatrics committee on infectious diseases, said the vote on thimerosal uses “selective” data and omits “established science (that) undermines public trust and fuels misinformation.”
“Taken in total, this speaks to a carefully plotted and executed strategy to advance an agenda to dismantle the vaccine infrastructure,” he said. “It is clear those of us who are dedicated to the health and wellbeing of Americans must work together without this leadership to continue the American success story.”
The liaison for the organization was not present at the June 25 or June 26 ACIP meetings. Despite being the only panel member to vote against the thimerosal recommendation, Meissner called their absence “childish” in a final comment that ended the meeting.
“In the past, the AAP has been very helpful in generating recommendations,” he said. “In the future, I strongly recommend the American Academy of Pediatrics to participate in these meetings as they always have.”
Contributing: Julie Steenhuysen and Michael Erman, Reuters
Adrianna Rodriguez can be reached at adrodriguez@usatoday.com.